Fluid-pressure brake.



J. W. CLOUD.

FLUID PRESSURE BRAKE.

APPLICATION FILED M1126, 1903.

Patented May 24, 1910.

WITH ESSE# UNITED sTATEs EATENT OFFICE.

JOHN VJIILI'.. CLOUD, OF LONDON. ENGLAND, ASSIGNOR TO THE WESTINGHOUSE.AIR

BRAKE COMPANY, OE PITTSBURG, PENNSYLVANIA, .A CORPORATION OF PENNSYL-VANIA.

FLUID-PRES URE BRAKE.

Speccation of Letters Patent.

Patented May 24, 1910.

Application led March 2G, 1903. Serial No. 149,691.

To all whom 'it may concern:

Be it known that I, JOHN \V. CLoUn, a citizen of the United States,residing in London, England, have invented a certain new and usefulImprotemcnz; in Fluid-Pressure Brakes, of which improvement thefollowing is a speciticaton.

. This invention relates to duid 'pressure brake apparatus for railwayand like vehicles and has for its object to provide a device by means ofwhich, withoutnecessarily altering existing brake mechanism of thisnature, a graduated release of the brakes after they have been ap lied,may be secured.

Brake apparatus of t e kind to which this invention relates is now wellknown, and need not therefore be referred to in detail. It comprisesessentially a brake cylinder, in which is located a piston, thc brakeshoes be'- ing connected to, the rod of this piston through rods andlevers, by means of which, when the piston is forced outward by airunder pressure admitted to the brake cylinder, the brake shoes areapplied to the 'wheels Sach brake apparatus further com prises anauxiliary reservoir, in which is stored air under pressure suppliedthrough a'main train pije 1 bm a main reservolr, 11i

- which a supplv of compgessed air is maintainedby a pu np, both ofthese latter being ,usually located on the engine.` The auxiliaryreservoir is connected to the train pipe and to the brake cylinderthrough a triple valve wnich is actuated to admit compressed air fromthe auxiliary reservoir to the brake cylinder in order to apply thebrakes when- 'evei the air pressure in the train pipe is reduced, and toexhaust the compressed air from the 4brake cylinder into the atmospherethrough a release port in Vthe triple valve when the pressure inthetrain pipe is restored, thereby releasing'tlie brakes.

According to niyhiiivention, in order to obtain a graduated'release ot'.the brakesd provide a devicecoiineeted with the train pine or auxiliaryreservoir which actuates a valve located zwtwccn the exhaih, portof thetriple valve, and the atmosphere, for the purpose of controlling theescape of air from the brake cylinder. Said valve 1s adapted to beopened and closed by variation in main train pipe press-ure and thepressure of the air escaping from the brake cylinder. In thcaccompanyingdrawings Figure 1 is a sectional view of one form of device constructedin accordance with my invention; Figs. 2 and 3 are similar views showingmodified forms ot the device illustrated in Fig. 1.

Similar reference numerals denote the saine parts in all the figures.

Referring now to Fig. 1, the device c0nsists of a reservoir 1, unintermediate casing Q, and an end casing 3, these three. parts beingarranged and connected together substantially in the manner shown. Thedevice may bc supported on the vehicle or attached to a convenient partof the brake apparatus in any suitable manner. Between the reservoir 1and the intermediate casing '2 is fixed a flexible diaphragm 4, anotherflexible dia phragiii 5 being fixed between the interiiiediate casing 2and the end casing 3. Abutting against the sides of these diaphragnisare plates 6, 7, 8, 9, having their surfaces adjacent to the diaphragins4, 5, slightly convex. The plates 7, 8, located between the diaphra rms4, 5, may be formed in one piece, tie connection between them being inthe form of a tubular stem lO and all the plates may be connectedtogether and securely held against the diaphrafrins by nicans of a rod11 and nuts 12, 13. ne end of the rod 11 is adapted to slide in anoritice 14 centrally located in that end of the reservoir 1 which isnearest the diaphragm 4, the other end sliding in a bearing formed iii aprojection 15 attached to the inside of the 'and casing 3 of the deviceby means of a nut 1G in the manner shown. This projection 15 has acentral cavity 17, communicating at one end with the atmosphere throughorif' :es 18, 19, in the casing 3 and at the other end with the interiorof the said easing through a valve seat 20, chamber 21 and openings 22.One end 23 of the rod 11 projects beyond the bearing in the projection15 above referred to into the chamber 21, and is adapted to coperatewith the valve seat '20 and act as a valveto cut ot communicationbetween the interior of the casing 3 ang an jection 15.

the atmosphere through the cavity 1T the orifices 18, 19. The projectionis provided with an external screw thread -alld an internally threadedcollar 2G snrection 15 through the intermediary of the locked nut '16. Aspring' 29 is inserted between the piston 9 and the collar 26, the

tension of which can be ad jnsted by altering the position of the collar26 in the manner above described. The interior of the casing 3 isarranged to communicate with the release port of the brake cylinder iuthe triple valve to which it may be 'connected by means of a pipeinserted into the opening 24 in said casing. The interior of theintermediate casing 2 communicates through the passage 30 with the mainpipe by a pipe inserted into the orilice 31. Communication between the.interior of the casing 2 and the reservoir 1 is also provided by meansof a passage 32, a check valve 33 being inserted 1n 'this passage inorder to prevent air under pressure flowing from the reservoir 1 intothe casing 2. The reservoir 1 communicates with the passage 30 leadingfrom the main pipe to the interior of the casing 2, through a assage 35in which .is located a loaded va ve 34. The pressure at which the valve34 willpermit air to pass from the reservoir 1, can be adjusted by meansof the spring 36. Upenings 37 are provided in that end of the reservoiradjacent to the diaphragm 4, so that the air under pressure in thereservoir may act on said diaphragm.

The operation of the device is as follows z--lVhen the brakes are fullyreleased, air under pressure will iow from the main train pipe of thebrake apparatus through the passage30, into the intermediate casing 2and also through the passage 32, past the check valve 33 into thercservoirl, until the pressure in the interior of the casing 2 andreservoir l is equal to the pressure existin the train pipe. Thediaphragm 4 consequently be in equilibrium. The pressure of the spring29 acting on the diaphragm 5, being slightly greater than the scquently,the

The pressure,` in n air pressure acting on the opposite side, will,under these circumstances, tend to maintain the parts in the positionshown in the drawing, that is to say, the valve 23 will be open. Inorder to apply the brakes. the pressure in the train pipe must bereduced, and, con- )ressuie in the intermediate be rorrespondingly'reduced. eservoir 1 will not, however, reduced, unless such a reductioncasing 2 will of pressure in the main pipe has been made as will leave adifference of ressu in the reservoir 1 sutlicient to o 'en t e loadedvalve A34. The greatest di erence of. pressure which can exist betweenthat in the reservoir l and the casing 2 .is obviously dependentl 70.upon the load on the valve 34. The excs o pressure in the reservoir lwill cause the diaphragms 4. and 5 to be moved to the right, and thereby'close the valve 23, it 'being understood that' under these circnn 7l5stances there is only atmospheric pressure in the end casing 3. 'Inorder to partially release the brakes, the pressure 1n the train pipemust be slightly increasedl and thev triple valve will then movel toallow ,the air 80 under pressure to exhaust from the brake cylinder,through the release port in theY triple valve into the interior of theend casing 3 by way of the orifice 24, owing t0 the connection existingbetween the latter and the release port of the triple valve. The, airunder increased pressure in the train pipe will also iiow into theintermediate casing 2, and as soon as the increased pressure in casing 2together with the pressure from thee() brake cylinder in the end casing3 prepon derates over the pressure existing in thereservoir 1, thediaphragm 5, aided by the spring 29, will be moved to the leftand thevalve 23 will be opened, thereby permitting 95 the air in the brakecylinder-to exhaust partially to the atmosphere. The v)ressure of airiiowing from the brake cylin er is, however, constantly decreasing; itfollows, therefore, that the pressure in the reservoir 1 will '100eventually again preponderate, and, acting c on the diaphragm 4 willclose the valve 23, and consequently the exhaust from the brake,cylinder,- so that the brakes will be only par` tially released. If nowthe ressure in the train pipe be again increase the increased 'pressurein chamber 2 acting on diaphragm 4 will establish a preponderance ofpressure which willhagain open valve 23'and permit a further reductionof pressure in-the brake cylinder before the superior pressure inreservoir 1 again closes valve 23.

'Referring now to Fig. 2 the .spring 29 which is shown in Fig. .1 forthe. purpose of balancing the pressure of the air in cham'- 115 berv 2on the diaphragm 5 and maintaining the valve 23 open when the pressurein chambers 1 and 2 1s equal, is dispensed with and in lieu thereof Iprovide an additional small chamber 40 open to the atmosphere through120 the orifice 41 and separated from the 'chamber 1 by a diaphragm 42.The diaphragm 42, which is connected by means of the plates 43, 44 androd 45 with the plate 6 and from thence through the rod 10 to the plate9, has 125 the same area as the diaphragnr, consequently the ressure ofthe aix* in chamber 2 en the diapli ragni 5 will be balanced by the 2 ition. It will be observe phragm 42.

pressure of air in chamber 1 on the aia- The valve 46 which differssomewhat in form from the corresponding valve 25 in Fig. 1 is notconnected to the diaphragm stem but is maintained in contact therewithby means of a light spring 47. The chamber 1 is also shown in Fig. l asbeing smaller and connected through an orifice 48 with a suitablereservoir 49. These modifications make no difference in the operation ofthe device which takes place 1n the same. manner as above described withreference to Fig. 1.

In Fig. 3 a further modified form of the device is shown. This formdiffers in -no essential particular from those shown in Figs. 1 and 2,either in Cprinciple or operathat in this form of the device the airescaping from the brake cylinder into the chamber 3 passes from thenceto a central channel 50, past the valve 46 into the chamber 40, and fromthence through orifice 19 to the atmosphere. In this construction, whenthe diaphragms and pistons are moved the valve 46 Will be opened byreason of its coming into contact with a stop 51. This stop ispreferably made adjustable, as shown.

Since while the brakes are being released, the auxiliary revervoirsthroughout the train are all in free communication with the main trainpipe owing td the fact that the triple valve is in the release position,it is clear that the pressure in the auxiliary reservoir will vary inthe same manner as the main pi )e pressure.. The chamber 2 of the graduarelease device may, therefore, be connected to the auxiliary reservoirinstead of to the train pipe, without altering the operation of thedevice.

It will be obvious that, by increasing the ressure of air in the trainipe by small increment-s, the pressure in tie brake cylinder may begradually reduced by corresponding increments and a graduated release ofthe brakes thus obtained.

With triple valves as ordinarily constructed, for use with fluidpressure brake apparatus, immediately the pressure in the train pipe isincreased for the purpose of releasin the brakes the parts are moved tothe re ease position, in which position the auxiliary reservoir is fedwith compressed air from thetrain pipe through the triple valve. It isobvious, therefore, that in fluid pressure brake ap aratus provided withthe device described a ove, while the brakes are being graduallyreleased, the auxiliary reservoir will be recharged with compressed airfrom the train pipe through the triple valve.

It will be seen that by the use of the device described above, ,loalteration to existing brake apparatus is necessary in order to obtain agraduated release of the brake.; It only necessary that the connectionsin dicated between the train pipe and the exhaust ort of the triplevalve should be made with t e device, in order to secure this result.Also the free and full release of the brake when desired is notinterfered with.

-I Wish it to be understood that I do noeV limit myself to theconstructions herein shown and described, as modifications may obviouslybe made therein without departing from the spirit and scope of myinventlon.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is 4 1. In a fluid ressure brake, the combina.-tion with a trip e valve having a brake cylinder exhaust port, of avalve for controlling said port, and'two diaphragms of different areassubject to the train pipe pressure for operating said valve, one of saiddiaphragms bein subjected on. its opposite side to pressure rom areservoir.

2. In a fluid Tressure brake, the combina.- tion with a triple valvehaving a brake cylinder exhaust port, of a. valve for controlling saidport, and two connected diaphragms o different areas for operating saidvalve, the space between said diaphragms communicating with the trainpire, and one of said diaphragms being Sulbjected on its opposite sideto pressure from a reservoir.

3. In a duid ressure brake, the combination with a trip e valve having abrake cy inder exhaust port, of. a valve for controlling said port, andtwo diaphragms for operating sai val-ve, the diaphragms being `subjecton their adjacent sides to train pipe pressure, one diaphragm sub'ect onits opposite side to pressure from t e triple valve exhaust, and theother diaphragm to pressure from a reservoir.

4. .In a fluid pressure brake, the combination with a triple valveexhaust port, of a. valve for controlling said port, a movable abutmentsubject to the opposing pressures of a reservoir and the train pipe andbrake cylinder for operating said valve, means for feeding` thereservoir from the train pipe, and a loaded valve between said reservoirand the train ipe chamber.

5. In a ui ressure brake, the combination with a bra e cylinder exhaustpassage and a valve controlling said passage, of a movable abutmentexposed on one sidc to train pipe ressure and on the opposite side to avariable fluid pressure, and another movable abutment exposed on oneside to brake c linder pressure, said valve being operate b bothabutments.

6. In a ililid ressure brake, the combination with a br e cylinderexhaust paage 4. esem.;

In testimony whereof I- have hereunto set my hand.

JOHN WILLS CLOUD.

Witnesses:

FREDERICK WILLIAM LE VALL, ARTHUR ALFRED BERGIN.

